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2ba45a60 DM |
1 | /* |
2 | * NC camera feed demuxer | |
3 | * Copyright (c) 2009 Nicolas Martin (martinic at iro dot umontreal dot ca) | |
4 | * Edouard Auvinet | |
5 | * | |
6 | * This file is part of FFmpeg. | |
7 | * | |
8 | * FFmpeg is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * FFmpeg is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with FFmpeg; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
23 | #include "libavutil/intreadwrite.h" | |
24 | #include "avformat.h" | |
25 | #include "internal.h" | |
26 | ||
27 | #define NC_VIDEO_FLAG 0x1A5 | |
28 | ||
29 | static int nc_probe(AVProbeData *probe_packet) | |
30 | { | |
31 | int size; | |
32 | ||
33 | if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG) | |
34 | return 0; | |
35 | ||
36 | size = AV_RL16(probe_packet->buf + 5); | |
37 | ||
38 | if (size + 20 > probe_packet->buf_size) | |
39 | return AVPROBE_SCORE_MAX/4; | |
40 | ||
41 | if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG) | |
42 | return AVPROBE_SCORE_MAX; | |
43 | ||
44 | return 0; | |
45 | } | |
46 | ||
47 | static int nc_read_header(AVFormatContext *s) | |
48 | { | |
49 | AVStream *st = avformat_new_stream(s, NULL); | |
50 | ||
51 | if (!st) | |
52 | return AVERROR(ENOMEM); | |
53 | ||
54 | st->codec->codec_type = AVMEDIA_TYPE_VIDEO; | |
55 | st->codec->codec_id = AV_CODEC_ID_MPEG4; | |
56 | st->need_parsing = AVSTREAM_PARSE_FULL; | |
57 | ||
58 | avpriv_set_pts_info(st, 64, 1, 100); | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
63 | static int nc_read_packet(AVFormatContext *s, AVPacket *pkt) | |
64 | { | |
65 | int size; | |
66 | int ret; | |
67 | ||
68 | uint32_t state=-1; | |
69 | while (state != NC_VIDEO_FLAG) { | |
70 | if (avio_feof(s->pb)) | |
71 | return AVERROR(EIO); | |
72 | state = (state<<8) + avio_r8(s->pb); | |
73 | } | |
74 | ||
75 | avio_r8(s->pb); | |
76 | size = avio_rl16(s->pb); | |
77 | avio_skip(s->pb, 9); | |
78 | ||
79 | if (size == 0) { | |
80 | av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n"); | |
81 | return AVERROR(EAGAIN); | |
82 | } | |
83 | ||
84 | ret = av_get_packet(s->pb, pkt, size); | |
85 | if (ret != size) { | |
86 | if (ret > 0) av_free_packet(pkt); | |
87 | return AVERROR(EIO); | |
88 | } | |
89 | ||
90 | pkt->stream_index = 0; | |
91 | return size; | |
92 | } | |
93 | ||
94 | AVInputFormat ff_nc_demuxer = { | |
95 | .name = "nc", | |
96 | .long_name = NULL_IF_CONFIG_SMALL("NC camera feed"), | |
97 | .read_probe = nc_probe, | |
98 | .read_header = nc_read_header, | |
99 | .read_packet = nc_read_packet, | |
100 | .extensions = "v", | |
101 | }; |